Display device

ABSTRACT

A display device includes a substrate, a transistor, a first insulating layer, a transfer pad, a second insulating layer, and a pixel electrode. The transistor is disposed on the substrate and includes a drain. The first insulating layer is disposed on the transistor and includes a first contact hole. The transfer pad is disposed on the first insulating layer and contacts the drain through the first contact hole. The transfer pad is filled into a bottom of the first contact hole to form a first contact region. The second insulating layer is disposed on the transfer pad and includes a second contact hole. A bottom of the second contact hole exposes part of the transfer pad to form a second contact region. The pixel electrode is disposed on the second insulating layer and contacts the transfer pad through the second contact hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Chinese patentapplication serial no. 202010457622.2, filed on May 26, 2020. Theentirety of the above-mentioned patent application is herebyincorporated by reference herein and made a part of this specification.

BACKGROUND Field of the Disclosure

The disclosure relates to a display device, and more particularly to adisplay device that can increase electron transmission between a pixelelectrode and a drain.

Description of Related Art

Flat display panels have been widely applied to electronic devices suchas mobile phones, televisions, monitors, tablet computers, car displays,wearable devices, and desktop computers. With the vigorous developmentof electronic products, the requirements for display quality ofelectronic products are higher and higher, and therefore improvement hasbeen made constantly to the electronic devices for display to achievethe display effect of greater and higher resolution.

SUMMARY OF THE DISCLOSURE

The disclosure provides a display device that can improve and stabilizethe electron transmission between the pixel electrode and the drain.

A display device includes a substrate, a transistor, a first insulatinglayer, a transfer pad, a second insulating layer, and a pixel electrode.The transistor is disposed on the substrate and includes a drain. Thefirst insulating layer is disposed on the transistor and includes afirst contact hole. The transfer pad is disposed on the first insulatinglayer and contacts the drain through the first contact hole. Thetransfer pad is filled into a bottom of the first contact hole to form afirst contact region. The first contact region has a first contact area.The second insulating layer is disposed on the transfer pad and includesa second contact hole. A bottom of the second contact hole exposes partof the transfer pad to form a second contact region. The second contactregion has a second contact area. The pixel electrode is disposed on thesecond insulating layer and contacts the transfer pad through the secondcontact hole. In the top view of the display device, the transfer padincludes the first contact region and the second contact region. Thesecond contact area is larger than the first contact area.

In order to make the above-mentioned features and advantages of thedisclosure more obvious and comprehensible, the embodiments aredescribed below with reference to the accompanying drawings for detaileddescription as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic top view of a display device according to anembodiment of the disclosure.

FIG. 1B is a schematic cross-sectional view of the display device ofFIG. 1A taken along section line A-A′.

FIG. 2A is a schematic top view of a display device according to anotherembodiment.

FIG. 2B is a schematic cross-sectional view of the display device ofFIG. 2A taken along section line B-B′.

FIG. 2C is a schematic cross-sectional view of the display device ofanother embodiment of FIG. 2A taken along the section line B-B′.

FIG. 2D is a schematic cross-sectional view of the display device ofanother embodiment of FIG. 2A taken along section line B-B′.

FIG. 3A is a schematic top view of a display device according to anotherembodiment.

FIG. 3B is a schematic cross-sectional view of the display device ofFIG. 3A taken along section line C-C′.

DESCRIPTION OF EMBODIMENTS

The disclosure can be understood by referring to the following detaileddescription in combination with the accompanying drawings. It should benoted that in order to make it easy for the reader to understand and forthe simplicity of the drawings, the multiple drawings in this disclosureonly depict a part of the electronic device, and the specific elementsin the drawings are not drawn according to actual scale. In addition,the number and size of each element in the drawings are only forexemplary purpose, and are not intended to limit the scope of thedisclosure.

In the following description and claims, the terms “contain” and“include” are open-ended terms, so they should be interpreted as“include but not limited to . . . ”.

It should be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, it can bedirectly set on said other element or layer or directly connected tosaid other element or layer, or there is an intervening element or layerbetween the two (indirect connection). In contrast, when an element isreferred to as being “directly on” or “directly connected to” anotherelement or layer, there are no intervening elements or layers betweenthe two.

Although the terms first, second, third . . . can be used to describe avariety of elements, the elements are not limited by this term. Thisterm is only used to distinguish a single element from other elements inthe specification. Different terminologies may be adopted in claims, andreplaced with the first, second, third . . . in accordance with theorder of elements specified in the claims. Therefore, in the followingdescription, the first element may be described as the second element inthe claims.

In some embodiments of the disclosure, terms such as “connect” and“interconnect” with respect to bonding and connection, unlessspecifically defined, may refer to two structures that are in directcontact with each other, or may refer to two structures that areindirectly in contact with each other, wherein there are otherstructures set between these two structures. In addition, the terms thatdescribe joining and connecting may apply to the case where bothstructures are movable or both structures are fixed. In addition, theterm “coupling” involves any direct and indirect electrical connectionmeans.

In the disclosure, the length and width can be measured by using anoptical microscope, and the thickness can be measured based on across-sectional image in an electron microscope, but not limited tothis. In addition, any two values or directions used for comparison mayhave certain errors.

The electronic device of the disclosure may include a display device, anantenna device, a sensing device, a touch display, a curved display or afree shape display, but not limited thereto. The electronic device maybe a bendable or flexible electronic device. The electronic device mayinclude, for example, light-emitting diodes, liquid crystal,fluorescence, phosphor, other suitable display media, or a combinationof the foregoing, but not limited thereto. The light-emitting diodes mayinclude, for example, organic light-emitting diodes (OLED), inorganiclight-emitting diodes (LED), mini light-emitting diodes (mini LED),micro light-emitting diodes (micro LED) or quantum dot (QD)light-emitting diodes (QLED or QDLED), or other suitable materials orany combination of the above, but not limited thereto. The displaydevice may include, for example, a spliced display device, but notlimited thereto. The antenna device may be, for example, a liquidcrystal antenna, but not limited thereto. The antenna device mayinclude, for example, an antenna spliced device, but not limitedthereto. It should be noted that the electronic device may be anycombination of the foregoing, but not limited thereto. In addition, theelectronic device may be in a rectangular shape, a circular shape, apolygonal shape, a shape with curved edges, or other suitable shapes.The electronic device may have peripheral systems such as a drivingsystem, a control system, a light source system, a shelf system, etc. tosupport the display device, the antenna device, or the spliced device.The disclosure will be explained below with reference to a displaydevice, but this disclosure is not limited thereto.

It should be noted that, the embodiments listed below can replace,recombine, and mix features in several different embodiments to achieveother embodiments without departing from the principle of thedisclosure. As long as the features in different embodiments are notagainst or in conflict with the principle of the disclosure, they can bemixed and used freely.

Reference will now be made in detail to exemplary embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same element symbols are used in thedrawings and description to denote the same or similar parts.

FIG. 1A is a schematic top view of a display device according to anembodiment of the disclosure. FIG. 1B is a schematic cross-sectionalview of the display device of FIG. 1A taken along section line A-A′. Forthe clarity of drawings and convenience of description, FIG. 1A omitsthe illustration of some elements in the display device.

Referring to FIG. 1A and FIG. 1B, the display device 100 of theembodiment includes a substrate 110, a transistor 120, a firstinsulating layer 130, a transfer pad 140, a second insulating layer 150,and a pixel electrode 160. In the embodiment, the substrate 110 mayinclude a rigid substrate or a flexible substrate. For example, thematerial of the substrate 110 may include glass, quartz, sapphire,ceramic, polycarbonate (PC), polyimide (PI), polyethylene terephthalate(PET), other suitable substrate materials, or a combination of theforegoing, but not limited thereto.

The transistor 120 is disposed on the substrate 110, and the transistor120 includes a gate GE, a gate insulating layer GI, a semiconductorlayer SE, a source SD1 and a drain SD2, but not limited thereto. In theembodiment, the gate insulating layer GI may have openings GIa and GIbto expose a part of the semiconductor layer SE. In some embodiments, thematerials of the source SD1 and/or the drain SD2 may include transparentconductive materials or non-transparent conductive materials, such asindium tin oxide, indium zinc oxide, indium oxide, zinc oxide, tinoxide, metal materials (such as aluminum, molybdenum, copper, silver,etc.), other suitable materials or a combination of the above, but notlimited thereto. In some embodiments, the material of the semiconductorlayer SE may include amorphous silicon, low temperature polysilicon(LTPS), metal oxide (e.g., indium gallium zinc oxide IGZO), othersuitable materials, or a combination of the above, but not limitedthereto. In the embodiment, although the gate GE of the transistor 120is a top gate structure, this disclosure is not limited thereto. That isto say, in other embodiments, the gate of the transistor may also be abottom gate structure. In addition, in the schematic top view of thisembodiment, the display device 100 further includes a scan line SL and aread line DL. The scan line SL and the read line DL are disposed on thesubstrate 110, and the scan line SL extends along a direction X, and theread line DL extends along a direction Y, wherein the direction X isdifferent from the direction Y. Since the gate GE of the transistor 120can be electrically connected to the scan line SL, and the source SD1 ofthe transistor 120 can be electrically connected to the read line DL,the transistor 120 can be electrically connected to the scan line SL andthe read line DL respectively.

In the embodiment, the display device 100 further includes a bufferlayer 170, a shielding layer 171, and a dielectric layer 172. The bufferlayer 170 and the shielding layer 171 are disposed between thetransistor 120 and the substrate 110, and the shielding layer 171 isdisposed corresponding to the gate GE. The dielectric layer 172 isdisposed between the source SD1 (or the drain SD2) and the gateinsulating layer GI to cover the gate GE and the gate insulating layerGI. The dielectric layer 172 may have openings 172 a and 172 b, whereinthe opening 172 a communicates with the opening GIa to expose a part ofthe semiconductor layer SE, and the opening 172 b communicates with theopening GIb to expose a part of the semiconductor layer SE.

In the embodiment, the source SD1 and the drain SD2 are respectivelydisposed on the dielectric layer 172. The source SD1 can also be filledin the opening 172 a of the dielectric layer 172 and the opening GIa ofthe gate insulating layer GI, so that the source SD1 can be electricallyconnected to the semiconductor layer SE. The drain SD2 can also befilled in the opening 172 b of the dielectric layer 172 and the openinghole GIb of the gate insulating layer GI, so that the drain SD2 can beelectrically connected to the semiconductor layer SE.

The first insulating layer 130 is disposed on the transistor 120. Thefirst insulating layer 130 covers the source SD1, the drain SD2, and thedielectric layer 172. The first insulating layer 130 and the substrate110 are respectively disposed on opposite sides of the transistor 120.The first insulating layer 130 includes a first contact hole 131, andthe first contact hole 131 exposes a part of the drain SD2.

The transfer pad 140 is disposed on the first insulating layer 130 andlocated between the pixel electrode 160 and the drain SD2. The transferpad 140 can also be filled in the first contact hole 131 of the firstinsulating layer 130, so that the transfer pad 140 can be electricallyconnected to the drain SD2. In the embodiment, the transfer pad 140 isdisposed corresponding to the drain SD2. The orthographic projection ofthe transfer pad 140 on the substrate 110 overlaps the orthographicprojection of the drain SD2 on the substrate 110, and the orthographicprojection of the transfer pad 140 on the substrate 110 is greater thanthe orthographic projection of the drain SD2 on the substrate 110. Inthe top view of the display device 100 (as shown in FIG. 1A), the areaof the transfer pad 140 is larger than the area of the drain SD2. In theembodiment, the material of the transfer pad 140 may include metalmaterials (such as aluminum, molybdenum, copper, silver, etc.), othersuitable materials, or a combination of the foregoing, but not limitedthereto.

The second insulating layer 150 is disposed on the transfer pad 140. Thesecond insulating layer 150 covers the transfer pad 140 and the firstinsulating layer 130. The second insulating layer 150 and the transistor120 are respectively disposed on opposite sides of the first insulatinglayer 130. The second insulating layer 150 includes a second contacthole 151, and the second contact hole 151 exposes a part of the transferpad 140.

The pixel electrode 160 is disposed on the second insulating layer 150,and located between the third insulating layer 180 and the secondinsulating layer 150. The pixel electrode 160 can also be filled in thesecond contact hole 151, so that the pixel electrode 160 can beelectrically connected to the transfer pad 140. The orthographicprojection of the pixel electrode 160 on the substrate 110 overlaps theorthographic projection of the transfer pad 140 on the substrate 110.

In the top view of the display device 100, the transfer pad 140 has afirst contact region 141 and a second contact region 142. The firstcontact region 141 is provided corresponding to the first contact hole131 of the first insulating layer 130. The second contact region 142 isprovided corresponding to the second contact hole 151 of the secondinsulating layer 150. Specifically, the portion where the transfer pad140 is filled in the bottom of the first contact hole 131 can beregarded as the first contact region 141 of the transfer pad 140. Thetransfer pad 140 has a first contact area in the first contact region141, and the part of the transfer pad 140 exposed from the bottom of thesecond contact hole 151 can be regarded as the second contact region 142of the transfer pad 140. The transfer pad 140 has a second contact areain the second contact region 142. In the embodiment, the area of thefirst contact region 141 may be equal to the area of the first contacthole 131, and the area of the second contact region 142 may be equal tothe area of the second contact hole 151, but not limited thereto.Therefore, the transfer pad 140 can contact the drain SD2 through thefirst contact hole 131 through the first contact region 141, and thepixel electrode 160 can contact the transfer pad 140 through the secondcontact hole 151 through the second contact region 142. That is, thepixel electrode 160 can be electrically connected to the drain SD2through the second contact region 142 and the first contact region 141of the transfer pad 140. In addition, in this embodiment, in the topview of the display device 100 (as shown in FIG. 1A), since the secondcontact area of the transfer pad 140 is larger than the first contactarea of the transfer pad 140, the configuration of the second contactregion 142 can increase the contact area between the pixel electrode 160and the transfer pad 140. In this manner, the pixel electrode 160 canimprove and stabilize the electron transmission between the pixelelectrode 160 and the drain SD2 through the second contact region 142 ofthe transfer pad 140.

In the embodiment, in the top view of the display device 100 (as shownin FIG. 1A), there is a distance D between the first contact hole 131 ofthe first insulating layer 130 and the second contact hole 151 of thesecond insulating layer 150, and the first contact hole 131 of the firstinsulating layer 130 does not overlap the second contact hole 151 of thesecond insulating layer 150. In addition, in the embodiment, the gate GEof the transistor 120 may be located between the first contact hole 131of the first insulating layer 130 and the second contact hole 151 of thesecond insulating layer 150, but not limited thereto.

In the embodiment, in the top view of the display device 100 (as shownin FIG. 1A), the transfer pad 140 further includes a first portion 143corresponding to the first contact hole 131 and a second portion 144corresponding to the second contact hole 151. Specifically, in the topview of the display device 100 (as shown in FIG. 1A), the transfer pad140 includes the first contact region 141 formed by the transfer pad 140filled in the first contact hole 131 as well as the first portion 143surrounding the first contact region 141, and the second contact region142 formed by the part of the transfer pad 140 exposed by the secondcontact hole 151 as well as the second portion 144 surrounding thesecond contact region 142. Specifically, the width W1 of the firstportion 143 may be smaller than the width W2 of the second portion 144,but not limited thereto. In the embodiment, in the top view of thedisplay device 100 (as shown in FIG. 1A), when the width W1 of the firstportion 143 of the transfer pad 140 is smaller than the width W2 of thesecond portion 144 of the transfer pad 140, specifically, the firstportion 143 and the second portion 144 of the transfer pad 140 of thisembodiment may be located on different sides of the scan line SL, andthe width W1 of the first portion 143 is smaller than the width W2 ofthe second portion 144, forming a contour with a gourd shape to reducecross-talk between the transfer pad 140 and the source SD1, but notlimited thereto. In addition, in the top view of the display device 100(as shown in FIG. 1A), the width W2 of the second portion 144 of thetransfer pad 140 may be greater than the width W3 of the second contacthole 151, and the width W1 of the first portion 143 of the transfer pad140 may be larger than the width W4 of the first contact hole 131. Inthis embodiment, the width W1 of the first portion 143, the width W2 ofthe second portion 144, the width W3 of the second contact hole 151, andthe width W4 of the first contact hole 131 are, for example, measuredalong the substantial extending direction (i.e., direction X) of thescan line SL.

In the embodiment, the display device 100 further includes a thirdinsulating layer 180 and a common electrode 181. The third insulatinglayer 180 is disposed on the pixel electrode 160 and in the secondcontact hole 151. The common electrode 181 is disposed on the thirdinsulating layer 180 and the second contact hole 151 so that the thirdinsulating layer 180 is located between the common electrode 181 and thepixel electrode 160.

In short, in the top view of the display device 100 of this embodiment,since the pixel electrode 160 can contact the second contact region 142of the transfer pad 140, and the first contact region 141 of thetransfer pad 140 can contact the drain SD2, the pixel electrode 160 canbe electrically connected to the drain SD2 through the second contactregion 142 and the first contact region 141 of the transfer pad 140. Inaddition, since the second contact region 142 of the transfer pad 140 islarger than the first contact region 141, the contact area between thepixel electrode 160 and the transfer pad 140 can be increased. In thismanner, the pixel electrode 160 can improve and stabilize the electrontransmission between the pixel electrode 160 and the drain SD2 throughthe second contact region 142 of the transfer pad 140, thereby reducingthe resistance between the pixel electrode 160 and the drain SD2.

Other embodiments are provided below for explanation. It should be notedhere that the following embodiments adopt the reference numbers andpartial contents of the foregoing embodiments, wherein the samereference numbers are used to indicate the same or similar elements, andthe description of the same technical content is omitted. For thedescription of the omitted parts, reference may be made to the foregoingembodiments, and the same content will not narrated in the followingembodiments.

FIG. 2A is a schematic top view of a display device according to anotherembodiment. FIG. 2B is a schematic cross-sectional view of the displaydevice of FIG. 2A taken along section line B-B′. Please refer to FIG. 1Aand FIG. 2A at the same time. The display device 100 a of thisembodiment is substantially similar to the display device 100 of FIG.1A, so the same and similar elements in the two embodiments will not bedescribed here. The display device 100 a of this embodiment differs fromthe display device 100 mainly in that the material of the transfer pad140 a of this embodiment may include a transparent conductive material,such as indium tin oxide, indium zinc oxide, indium oxide, zinc oxide,tin oxide, other suitable materials, or a combination of the above, butnot limited thereto.

In detail, please refer to FIG. 2A. In the top view of the displaydevice 100 a, the transfer pad 140 a of the display device 100 aincludes a first portion 143 a corresponding to the first contact hole131 and a second portion 144 a corresponding to the second contact hole151, wherein the width W1′ of the first portion 143 a is equal to thewidth W2′ of the second portion 144 a. Specifically, the first portion143 a and the second portion 144 a of the transfer pad 140 of thisembodiment may be located on different sides of the scan line SL, andthe width W1′ of the first portion 143 a and the width W2′ of the secondportion 144 a may be the same, forming a contour with a rectangularshape, but not limited thereto. The width W2′ of the second portion 144a of the transfer pad 140 a is larger than the width W3 of the secondcontact hole 151. Under the circumstances, the contour of the transferpad 140 a may be a rectangular shape, but not limited thereto. In thisembodiment, the width W1′ of the first portion 143 a, the width W2′ ofthe second portion 144 a, and the width W3 of the second contact hole151 are, for example, measured along the substantial extending direction(i.e., direction X) of the scan line SL.

Please refer to FIG. 2A and FIG. 2B at the same time. In thisembodiment, since there is a distance D′ between the transfer pad 140 aand the source SD1 (DL), the parasitic capacitance between the transferpad 140 a and the source SD1 (DL) can be reduced, thereby decreasing thecross-talk between the transfer pad 140 a and the source SD1.Additionally, further refer to FIG. 2B, in the cross-sectional view ofthe display device 100 a, since the width W2′ of the second portion 144a of the transfer pad 140 a is larger than the width W3 of the secondcontact hole 151 and the orthographic projection of the transfer pad 140a on the substrate 110 may partially overlap the orthographic projectionof the second insulating layer 150 on the substrate 110, the thirdinsulating layer 180 in the second contact hole 151 may be formedbetween the pixel electrode 160 and the common electrode 181. In thismanner, it is possible to avoid the risk of short circuit caused by thecontact between the pixel electrode 160 and the common electrode 181. Inthis embodiment, the width W2′ of the transfer pad 140 a may also begreater than the width W6 of the pixel electrode 160, but not limitedthereto. On the contrary, when the width W2′ of the second portion 144 aof the transfer pad 140 a is smaller than the width W3 of the secondcontact hole 151 and the orthographic projection of the transfer pad 140a on the substrate 110 does not partially overlap the orthographicprojection of the second insulating layer 150 on the substrate 110, thethird insulating layer 180 in the second contact hole 151 may becracked, and consequently the pixel electrode 160 may contact the commonelectrode 181 and cause a short circuit. In this embodiment, the widthW3 of the second contact hole 151, the width W2′ of the transfer pad 140a, and the width W6 of the pixel electrode 160 are measured along thedirection X, for example.

FIG. 2C is a schematic cross-sectional view of the display device ofanother embodiment of FIG. 2A taken along the section line B-B′. Pleaserefer to FIG. 2B and FIG. 2C at the same time, the display device 100 bof this embodiment is substantially similar to the display device 100 aof FIG. 2B, so the same and similar elements in the two embodiments willnot be described here. The display device 100 b of this embodimentdiffers from the display device 100 a mainly in that, in the displaydevice 100 b of this embodiment, the width W5 of the transfer pad 140 bis smaller than the width W3 of the second contact hole 151 b of thesecond insulating layer 150 b.

In detail, please refer to FIG. 2C, since the width W5 of the transferpad 140 b is smaller than the width W3 of the second contact hole 151 bof the second insulating layer 150 b, the distance between the transferpad 140 b and the source SD1 can be increased, thus further reducing theparasitic capacitance between the transfer pad 140 b and the source SD1,and the cross-talk between the transfer pad 140 b and the source SD1 canbe further decreased. In addition, in the second contact hole 151 b ofthe second insulating layer 150 b, the width W5 of the transfer pad 140b may also be smaller than the width W6 of the pixel electrode 160 b,but not limited thereto. In this embodiment, since the width W5 of thetransfer pad 140 b can be smaller than the width W6 of the pixelelectrode 160 b, the subsequently formed pixel electrode 160 b and thethird insulating layer 180 can be disposed on the transfer pad 140 b,and the third insulating layer 180 can completely cover the transfer pad140 b and the pixel electrode 160 b in the second contact hole 151 b,but not limited thereto. In this embodiment, the width W3 of the secondcontact hole 151 b, the width W5 of the transfer pad 140 b, and thewidth W6 of the pixel electrode 160 b are measured along the directionX, for example.

FIG. 2D is a schematic cross-sectional view of the display device ofanother embodiment of FIG. 2A taken along section line B-B′. Referringto FIG. 2C and FIG. 2D at the same time, the display device 100 c ofthis embodiment is substantially similar to the display device 100 b ofFIG. 2C, so the same and similar elements in the two embodiments willnot be repeated here. The display device 100 c of this embodiment isdifferent from the display device 100 b mainly in that, in the secondcontact hole 151 c of the second insulating layer 150 c of the displaydevice 100 c of this embodiment, the width W5 of the transfer pad 140 cis larger than the width W6′ of the pixel electrode 160 c. In thisembodiment, the width W5 of the transfer pad 140 c and the width W6′ ofthe pixel electrode 160 c are measured along the direction X, forexample.

FIG. 3A is a schematic top view of a display device according to anotherembodiment. FIG. 3B is a schematic cross-sectional view of the displaydevice of FIG. 3A taken along section line C-C′. Please refer to FIG.1B, FIG. 2A and FIG. 3A to FIG. 3B at the same time. The display device100 d of this embodiment is substantially similar to the display device100 of FIG. 1B and the display device 100 a of FIG. 2A, so the same andsimilar elements in the two embodiments are not described here. Thedisplay device 100 d of this embodiment is different from the displaydevices 100 and 100 a mainly in that the display device 100 d of thisembodiment further includes a read line DL′ and a fourth insulatinglayer 190.

In detail, please refer to FIG. 3A and FIG. 3B at the same time. Theread line DL′ is disposed on the first insulating layer 130 and locatedbetween the fourth insulating layer 190 and the first insulating layer130. The read line DL′ is disposed corresponding to the source SD1 (readline DL). The orthographic projection of the read line DL′ on thesubstrate 110 overlaps the orthographic projection of the source SD1(read line DL) on the substrate 110. In this embodiment, the material ofthe read line DL′ may include metal materials (e.g., aluminum,molybdenum, copper, silver, etc.), other suitable materials, or acombination of the foregoing, but not limited thereto.

The fourth insulating layer 190 is provided on the read line DL′. Thefourth insulating layer 190 covers the read line DL′ and the firstinsulating layer 130. The fourth insulating layer 190 and the transistor120 are respectively disposed on opposite sides of the first insulatinglayer 130. The fourth insulating layer 190 includes a third contact hole191, wherein the third contact hole 191 communicates with the firstcontact hole 131 to expose a part of the drain SD2.

The transfer pad 140 d is disposed on the fourth insulating layer 190,and filled in the third contact hole 191 and the first contact hole 131.The transfer pad 140 d is disposed between the second insulating layer150 and the fourth insulating layer 190. The transfer pad 140 d isdisposed corresponding to the drain SD2. The orthographic projection ofthe transfer pad 140 d on the substrate 110 overlaps the orthographicprojection of the drain SD2 on the substrate 110, and the orthographicprojection of the transfer pad 140 on the substrate 110 is greater thanthe orthographic projection of the drain SD2 on the substrate 110. Inthe top view of the display device 100 d (as shown in FIG. 3A), the areaof the transfer pad 140 d is larger than the area of the drain SD2. Inthis embodiment, the material of the transfer pad 140 d may include atransparent conductive material, such as indium tin oxide, indium zincoxide, indium oxide, zinc oxide, tin oxide, other suitable materials, ora combination of the above, but not limited thereto.

In this embodiment, by setting the read line DL′ on the source SD1 (readline DL) and making the read line DL′ correspond to the source SD1 (readline DL), the display device 100 d of this embodiment can be providedwith double-layer read lines DL and DL′. Therefore, the display device100 d of this embodiment with the double-layer read lines DL and DL′ canreduce the impedance through the electrical connection between DL andDL′ (not shown), thereby enhancing the driving capability of panel.Specifically, in a display panel with a small pixel size, since thewidth of the read line is smaller than that of a display panel with alarge pixel size, when it is desired to achieve a display panel of asmall pixel size with high resolution, the loading of the read line ofsuch display panel will be significantly higher than the loading of theread line of the display panel of a large pixel size, and consequentlythe loading of the read line is likely to be excessively high and thescreen display will be abnormal. Therefore, according to the teaching ofthis embodiment, if the double-layer read lines are provided in adisplay panel with a small pixel size and the electrical connectiondesign is applied to the double-layer read lines, the impedance can bereduced and the driving capability of panel can be increased. In thismanner, the requirement for small pixel size and high resolution can besatisfied simultaneously. For example, in a virtual reality (VR) displaypanel with a small pixel size, when the display panel is driven at ascreen refresh rate at a higher resolution (such as 3K, but not limitedthereto) or the computer game requires the application of a screenrefresh rate at a higher frequency (for example, greater than 60 Hz, butnot limited thereto), the screen display is likely to be abnormal due tothe excessively high loading of the read lines. Therefore, thedouble-layer read line design is required to reduce impedance andimprove driving capability of the panel.

In summary, in the display device of the embodiment of the disclosure,because the pixel electrode can contact the second contact region of thetransfer pad, and the first contact region of the transfer pad cancontact the drain, the pixel electrode can be electrically connected tothe drain through the second contact region and the first contact regionof the transfer pad. In addition, since the second contact region of thetransfer pad is larger than the first contact region, the contact areabetween the pixel electrode and the transfer pad can be increased.Therefore, the display device of this embodiment can increase thecontact area between the pixel electrode and the transfer pad by settingthe second contact region of the transfer pad, so that the pixelelectrode can improve and stabilize the electron transmission betweenthe pixel electrode and the drain through the second contact region ofthe transfer pad, and reduce the resistance between the pixel electrodeand the drain to improve the display quality of high-pixel displaydevices.

Although the disclosure has been disclosed in the above embodiments, itis not intended to limit the disclosure, and those skilled in the artcan make some modifications and refinements without departing from thespirit and scope of the disclosure. Therefore, the scope of thedisclosure is subject to the definition of the scope of the appendedclaims.

What is claimed is:
 1. A display device, comprising: a substrate; atransistor disposed on the substrate and comprising a drain; a firstinsulating layer disposed on the transistor and comprising a firstcontact hole; a transfer pad disposed on the first insulating layer andcontacting the drain through the first contact hole; a second insulatinglayer disposed on the transfer pad and comprising a second contact hole;and a pixel electrode disposed on the second insulating layer andcontacting the transfer pad through the second contact hole; wherein ina top view of the display device, the transfer pad comprises a firstcontact region and a second contact region, wherein the transfer pad isfilled into a bottom of the first contact hole to form the first contactregion, and a bottom of the second contact hole exposes a part of thetransfer pad to form the second contact region, wherein the firstcontact region has a first contact area, the second contact region has asecond contact area, and the second contact area is larger than thefirst contact area.
 2. The display device according to claim 1, whereinin the top view of the display device, the first contact hole does notoverlap the second contact hole.
 3. The display device according toclaim 1, wherein in the top view of the display device, an area of thetransfer pad is larger than an area of the drain.
 4. The display deviceaccording to claim 1, wherein the transfer pad comprises a metalmaterial.
 5. The display device according to claim 4, in the top view ofthe display device, the transfer pad further comprises a first portionand a second portion, wherein the first portion is providedcorresponding to the first contact hole, and the second portion isprovided corresponding to the first contact hole, and a width of thefirst portion is smaller than a width of the second portion.
 6. Thedisplay device according to claim 1, wherein the transfer pad comprisesa transparent conductive material.
 7. The display device according toclaim 6, wherein in the top view of the display device, the transfer padfurther comprises a first portion and a second portion, wherein thefirst portion is provided corresponding to the first contact hole, thesecond portion is provided corresponding to the first contact hole, anda width of the first portion is equal to a width of the second portion.8. The display device according to claim 1, wherein in the top view ofthe display device, a width of the transfer pad is larger than a widthof the second contact hole.
 9. The display device according to claim 1,wherein in a cross-sectional view of the display device, in the secondcontact hole, a width of the transfer pad is smaller than a width of thepixel electrode.
 10. The display device according to claim 1, wherein ina cross-sectional view of the display device, in the second contacthole, a width of the transfer pad is larger than a width of the pixelelectrode.